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Recovery strategy for the blue whale (Balaenoptera musculus), Northwest Atlantic population, in Canada

Appendices

Appendix 1. Classification of threats by order of priority

Each threat is defined according to these 12 criteria:

Threat category: Broad category indicating the type of threat.

General threat: General activity causing the specific threat.

Specific threat: The specific factor or stimulus causing stress to the population.

Stress: Indicated by an impairment of a demographic, physiological, or behavioural attribute of a population in response to an identified or unidentified threat that results in a reduction of the population viability.

Extent: Indicate whether the threat is widespread, localized, or unknown across the species range.

Occurrence: Indicate whether the threat is historic (contributed to decline but no longer affecting the species), current (affecting the species now), imminent (is expected to affect the species very soon), anticipated (may affect the species in the future), or unknown.

Frequency: Indicate whether the threat is a one-time occurrence, seasonal (either because the species is migratory or the threat only occurs at certain times of the year – indicate which season), continuous (on-going), recurrent (reoccurs from time to time but not on an annual or seasonal basis) or unknown.

Causal certainty: Indicate whether the best available knowledge about the threat and its impact on population viability is high (evidence causally links the threat to stresses on population viability), medium (correlation between the threat and population viability, expert opinion, etc), or low (assumed or plausible threat only).

Severity: Indicate whether the severity of the threat is high (very large population-level effect), moderate, low, or unknown.

Level of concern: Indicate whether managing the threat is an overall high, medium, or low concern for recovery of the species, taking into account all of the above factors.

Local: Indicates threat information relates to a specific site or narrow portion of the range of the species.

Range-wide: Indicates threat information relates to the whole distribution or large portion of the range of the species.


Anthropogenic threats

1) Anthropogenic noise: Acoustic degradation and changes in blue whale behaviour
Threat category:
Loss or degradation of habitat; disturbance
Overall threat:
Low frequency anthropogenic noise (e.g., shipping, seismic exploration, oil and gas development, and military sonars)
Specific threat:
Change in behaviour or habitat characteristics
Stress:
Change in behaviour and risk of abandoning the critical habitat
Range:
Generalized
Occurrence:
Current
Frequency:
Continuous
Causal certainty:
Medium to high
Severity
Unknown
Level of concern:
High

2) Food availability
Threat category:
Consumption; climate and natural disasters; natural activities or processes
Overall threat:
Krill fishery; climate change; competing with pelagic fish
Specific threat:
Influences krill distribution and abundance
Stress:
Reducing food resource availability for blue whales which leads to decreased physical condition which could impact reproductive success and the ability to migrate.
Range:
Generalized
Occurrence:
Current
Frequency:
Continuous
Causal certainty:
Low to high
Severity
Unknown
Level of concern:
High

3) Contaminants
Threat category:
Pollution
Overall threat:
Agricultural, industrial and municipal waste, shipping, dredging, oil and gas development, aquaculture
Specific threat:
Changes to habitat characteristics and water chemistry; direct exposure; consumption of contaminated prey
Stress:
Depression of the immune system, cancer and lesions; reduced reproductive capacity
Range:
Generalized
Occurrence:
Current
Frequency:
Continuous
Causal certainty:
Low
Severity
Unknown
Level of concern:
Medium

4) Collisions with vessels
Threat category:
Accidental mortalities
Overall threat:
Collisions with vessels
Specific threat:
Vessels traveling at high speeds (i.e., 14 knots or more)
Stress:
Increased injuries and mortalities
Range:
Localized
Occurrence:
Current
Frequency:
Continuous
Causal certainty:
Medium
Severity
Moderate
Level of concern:
Medium

5) Whale-watching
Threat category:
Disturbance or persecution
Overall threat:
Whale-watching activities by cruise operators, recreational boaters and scientists
Specific threat:
Disturbing critical activities (e.g., rest, feeding, communication, socializing, mating and nurturing calves)
Stress:
Change in behaviour or abandoning habitat
Range:
Localized
Occurrence:
Current
Frequency:
Seasonal
Causal certainty:
Medium to high
Severity
Moderate
Level of concern:
Medium

6) Anthropogenic noise: physical damage
Threat category:
Accidental mortalities
Overall threat:
Low frequency or high amplitude anthropogenic noise (e.g., seismic exploration, oil and gas development, and military sonars)
Specific threat:
Physical harm leading to hearing loss and death
Stress:
Injuries, mortalities, reduced population sustainability
Range:
Generalized
Occurrence:
Current
Frequency:
Continuous
Causal certainty:
Medium
Severity
Unknown
Level of concern:
Low

7) Accidental entanglement in fishing gear
Threat category:
Accidental mortalities
Overall threat:
Fishery
Specific threat:
Entanglement in fishing gear (e.g., gillnets)
Stress:
Injuries, change in behaviour or mortality
Range:
Generalized
Occurrence:
Current
Frequency:
Continuous
Causal certainty:
Medium
Severity
Unknown
Level of concern:
Low

8) Epizootics and toxic algal blooms
Threat category:
Changes in the ecological dynamics or natural processes
Overall threat:
Epizooty and toxic algal blooms
Specific threat:
Health problems and toxic effects for blue whales
Stress:
Reduced physical condition and increased mortalities
Range:
Generalized
Occurrence:
Anticipated
Frequency:
Unknown
Causal certainty:
Unknown
Severity
Unknown
Level of concern:
Low

9) Toxic spills
Threat category:
Pollution
Overall threat:
Toxic product spills
Specific threats:
Direct exposure; consumption of contaminated prey; changes to habitat characteristics
Stress:
Toxic and physiological effects, reduced physical condition, mortalities
Range:
Generalized
Occurrence:
Anticipated
Frequency:
Recurrent
Causal certainty:
Medium
Severity
Low to moderate
Level of concern:
Low


Whaling and natural mortality

10) Whaling
Threat category:
Consumption
Overall threat:
Whaling
Specific threat:
Commercial, scientific or subsistence whaling
Stress:
Mortalities which lead to a significant drop in terms of numbers of individuals and reduced population sustainability
Range:
Generalized
Occurrence:
Historical in Canada, but still ongoing or anticipated in all the distribution range
Frequency:
Abandoned in Canada, but possibly still ongoing in certain areas of the distribution range
Causal certainty:
High
Severity
High
Level of concern:
Low

11) Ice
Threat category:
Natural activities or process
Overall threat:
The creation of a layer of ice or the movement of the ice layer
Specific threat:
Entrapment of blue whales under the ice layer
Stress:
Reduced physical condition (i.e., injuries) or death by anoxia or crushing by ice blocks
Range:
Localized
Occurrence:
Current locally, but not for the entire range
Frequency:
Seasonal
Causal certainty:
High
Severity
Moderate
Level of concern:
Medium

12) Predation
Threat category:
Natural activity or process
Overall threat:
Predation of individuals
Specific threat:
Killer whales
Stress:
Reduced physical condition (i.e., injuries) or increased mortalities
Range:
Localized
Occurrence:
Current
Frequency:
Recurrent
Causal certainty:
Low
Severity
Low
Level of concern:
Low


Appendix 2. Cetacean species present in the canadian atlantic

Table 3. Status of marine mammal species assessed by the COSEWIC that visit the St. Lawrence and Atlantic Ocean
Common name (population)Scientific nameCOSEWIC assessmentCOSEWIC designationSARA status
Atlantic white-sided dolphinLagenorhynchus acutusApril 1991Not at riskNo status
Beluga whale (St. Lawrence estuary)Delphinapterus leucasMay 2004ThreatenedThreatened
Beluga whale (Ungava Bay)Footnote aDelphinapterus leucasMay 2004EndangeredNo status
Beluga whale (Eastern Hudson Bay)Footnote aDelphinapterus leucasMay 2004EndangeredNo status
Blainville’s beaked whaleFootnote aMesoplodon densirostrisApril 1989Not at riskNo status
Blue whale (Atlantic)Balaenoptera musculusMay 2002EndangeredEndangered
Common dolphinFootnote aDelphinus delphisApril 1991Not at riskNo status
Cuvier’s beaked whaleFootnote aZiphius cavirostrisApril 1990Not at riskNo status
Dolphin bottlenoseFootnote aTursiops truncatusApril 1993Not at riskNo status
Fin whale (Atlantic)Balaenoptera physalusMay 2005Special concernSpecial concern
Grey whale (Atlantic)Footnote aEschrichtius robustusMay 2000ExtirpatedExtirpated
Harbour porpoise (Northwest Atlantic)Phocoena phocoenaApril 2006Special concernNo status
Humpback whale (North Atlantic)Megaptera novaeangliaeMay 2003Not at riskNo status
Killer whale (Northwest Atlantic)Orcinus orcaNovember 2001Data deficientNo status
Long-finned pilot whaleGlobicephala melasApril 1994Not at riskNo status
Minke whale (Atlantic)Balaenoptera acutorostrataApril 2006Not at riskNo status
North Atlantic right whaleEubalaena glacialisMay 2003EndangeredEndangered
Northern bottlenose whale (Scotian Shelf population)Hyperoodon ampullatusNovember 2002EndangeredEndangered
Northern bottlenose whale (Davis Strait)Footnote aHyperoodon ampullatusApril 1993Not at riskNo status
Pygmy sperm whaleFootnote aKogia brevicepsApril 1994Not at riskNo status
Sei whale (Atlantic)Footnote aBalaenoptera borealisMay 2003Data deficientNo status
Sowerby’s beaked whaleFootnote aMesoplodon bidensNovember 2006Special concernSpecial concern
Sperm whalePhyseter macrocephalusApril 1996Not at riskNo status
Striped dolphinFootnote aStenella coeruleoalbaApril 1993Not at riskNo status
True’s beaked whaleFootnote aMesoplodon mirusApril 1989Not at riskNo status
White-beaked dolphinLagenorhynchus albirostrisApril 1998Not at riskNo status

Footnotes

Footnote A

Species or populations present in the Atlantic, but absent from the Estuary and Gulf of St. Lawrence.

Return to footnote a

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